That's not to say collecting is unethical. It's just tricky. For one, "not everything is the Mona Lisa," Jakab says. So long as they're properly preserved—kept in a humidity-controlled environment, say, or handled with gloves—"mundane" or "garden variety" historical objects should be fair game. In some cases, collectors become experts in their area of interest, and collaborate with curators in the same field. "I can assure you, people with private collections love to talk about them," Jakab jokes. Most importantly, private owners can share their objects with the public in different ways. "When you, say, put an airplane in a museum, it's not going to fly again," Jakab says. "But if you had a historical example that's in private collection… you could hear the motor, see how it flies, and there's great value in that as well." Jakab himself is a collector of antique cars. "As we say, you don't own the car, you just maintain it until the next person has it after you."